Matrix metalloproteinase 2 may be a marker of microangiopathy in children and adolescents with type 1 diabetes mellitus

Matrix metalloproteinases (MMPs) 2 and 9 are responsible for extracellular matrix breakdown and their abnormal circulating levels may pre-date clinical evidence of diabetic angiopathy. We detected by ELISA, plasma MMP-2 and MMP-9 levels and associated activity in 25 children and adolescents with T1DM. Thirteen male and 12 female patients were evaluated at the clinical diagnosis and onset of T1DM and again at a 5-year follow-up. Twelve patients had developed microangiopathic complications at the follow-up evaluation. MMP-2 and MMP-9 levels and activity were detected in samples obtained at T1DM diagnosis and at the 5-year follow-up. As controls, 19 healthy subjects who were the same age as the patients were also evaluated at baseline and again after 5 years. MMP-2 levels and activity were significantly higher in the patients than in the controls at disease onset. This was particularly evident when patients who developed microangiopathic complications were compared to controls and patients without complications. At the 5-year follow-up, a significant increase in MMP-2 levels and a significant decrease in MMP-2 activity were found only in the control group compared to the baseline levels. MMP-2 levels and activity were higher in patients with microangiopathy. MMP-9 levels and activity were increased in all groups compared to baseline levels. MMP-9 levels were lower in patients with microangiopathy compared to controls, but no difference was found between the two patient groups. It is well known that MMP-9 is an index of the severity and stability of macroangiopathy while our results allow us to postulate that MMP-2 may be a marker of microangiopathy.